added preset saving and heat transfer

app.py

@@ -9,13 +9,14 @@ POST /api/sweep        → run sweep_operating_points(), return JSON dataset
 """
 
 import base64
+import json
 import math
 import os
 import tempfile
 
 from flask import Flask, render_template, request, jsonify
 
-from designer import ToroidCore, WindingSpec, design_transformer
+from designer import ToroidCore, WindingSpec, WireSpec, design_transformer
 from sim_toroid import (
     ToroidSimulator, SimConstraints,
     sweep_operating_points, SweepEntry,
@@ -61,12 +62,30 @@ def _parse_windings(data: dict) -> list[WindingSpec]:
     return specs
 
 
-def _drawing_b64(core: ToroidCore, results) -> str:
+def _actual_fill_factor(core: ToroidCore, results) -> float:
+    """
+    Compute actual fill factor = total wire cross-section area placed / window area.
+    Sums wire area for every turn placed across all windings.
+    """
+    window_area = core.window_area_mm2
+    if window_area <= 0:
+        return 0.0
+    total_wire_area = 0.0
+    for wr in results:
+        for seg in wr.segments:
+            wire = WireSpec.from_awg(seg.awg)
+            r = wire.diameter_mm / 2.0
+            total_wire_area += math.pi * r * r * seg.turns
+    return total_wire_area / window_area
+
+
+def _drawing_b64(core: ToroidCore, results, actual_fill: float) -> str:
     """Render the toroid PNG and return it as a base64 data-URI string."""
     with tempfile.NamedTemporaryFile(suffix=".png", delete=False) as f:
         tmp_path = f.name
     try:
-        draw_toroid(core, results, output_path=tmp_path, dpi=150, fig_size_mm=160)
+        draw_toroid(core, results, output_path=tmp_path, dpi=150, fig_size_mm=160,
+                    actual_fill=actual_fill)
         with open(tmp_path, "rb") as f:
             png_bytes = f.read()
     finally:
@@ -156,13 +175,28 @@ def api_design():
 
         results = design_transformer(core, specs, fill_factor=fill_factor)
 
-        drawing_b64 = _drawing_b64(core, results)
+        actual_fill = _actual_fill_factor(core, results)
+        drawing_b64 = _drawing_b64(core, results, actual_fill)
         windings_info = [_winding_result_to_dict(wr) for wr in results]
 
+        # Thermal surface area of wound toroid (m²):
+        # outer cylinder + top/bottom annular faces + inner bore cylinder
+        OD_m = core.OD_mm * 1e-3
+        ID_m = core.ID_mm * 1e-3
+        H_m  = core.height_mm * 1e-3
+        A_outer  = math.pi * OD_m * H_m
+        A_faces  = 2 * math.pi / 4 * (OD_m**2 - ID_m**2)
+        A_bore   = math.pi * ID_m * H_m
+        A_surface_m2 = A_outer + A_faces + A_bore
+
         return jsonify({
             "success": True,
             "windings": windings_info,
             "drawing": drawing_b64,
+            "fill_factor_target": fill_factor,
+            "fill_factor_actual": round(actual_fill, 4),
+            "window_area_mm2": round(core.window_area_mm2, 2),
+            "A_surface_m2": round(A_surface_m2, 6),
         })
 
     except Exception as exc:
@@ -259,5 +293,93 @@ def api_sweep():
                         "traceback": traceback.format_exc()}), 400
 
 
+# ---------------------------------------------------------------------------
+# Preset persistence
+# ---------------------------------------------------------------------------
+
+PRESETS_DIR = os.path.join(os.path.dirname(__file__), "presets")
+os.makedirs(PRESETS_DIR, exist_ok=True)
+
+# Valid preset categories
+_PRESET_TYPES = {"core", "windings", "constraints", "sim"}
+
+
+def _preset_path(ptype: str) -> str:
+    return os.path.join(PRESETS_DIR, f"{ptype}.json")
+
+
+def _load_store(ptype: str) -> dict:
+    """Load the JSON store for a preset type; return {} on missing/corrupt."""
+    path = _preset_path(ptype)
+    if not os.path.exists(path):
+        return {}
+    try:
+        with open(path, "r", encoding="utf-8") as f:
+            return json.load(f)
+    except Exception:
+        return {}
+
+
+def _save_store(ptype: str, store: dict) -> None:
+    path = _preset_path(ptype)
+    with open(path, "w", encoding="utf-8") as f:
+        json.dump(store, f, indent=2)
+
+
+@app.route("/api/presets/<ptype>", methods=["GET"])
+def presets_list(ptype: str):
+    """Return list of saved preset names and the last-used name."""
+    if ptype not in _PRESET_TYPES:
+        return jsonify({"success": False, "error": f"Unknown type '{ptype}'"}), 400
+    store = _load_store(ptype)
+    names = [k for k in store if not k.startswith("_")]
+    last = store.get("_last", None)
+    return jsonify({"success": True, "names": sorted(names), "last": last})
+
+
+@app.route("/api/presets/<ptype>/<name>", methods=["GET"])
+def presets_load(ptype: str, name: str):
+    """Load a named preset and mark it as last-used."""
+    if ptype not in _PRESET_TYPES:
+        return jsonify({"success": False, "error": f"Unknown type '{ptype}'"}), 400
+    store = _load_store(ptype)
+    if name not in store:
+        return jsonify({"success": False, "error": f"Preset '{name}' not found"}), 404
+    store["_last"] = name
+    _save_store(ptype, store)
+    return jsonify({"success": True, "name": name, "data": store[name]})
+
+
+@app.route("/api/presets/<ptype>/<name>", methods=["POST"])
+def presets_save(ptype: str, name: str):
+    """Save (create or overwrite) a named preset and mark it as last-used."""
+    if ptype not in _PRESET_TYPES:
+        return jsonify({"success": False, "error": f"Unknown type '{ptype}'"}), 400
+    if not name or name.startswith("_"):
+        return jsonify({"success": False, "error": "Invalid preset name"}), 400
+    data = request.get_json(force=True)
+    store = _load_store(ptype)
+    store[name] = data
+    store["_last"] = name
+    _save_store(ptype, store)
+    return jsonify({"success": True, "name": name})
+
+
+@app.route("/api/presets/<ptype>/<name>", methods=["DELETE"])
+def presets_delete(ptype: str, name: str):
+    """Delete a named preset."""
+    if ptype not in _PRESET_TYPES:
+        return jsonify({"success": False, "error": f"Unknown type '{ptype}'"}), 400
+    store = _load_store(ptype)
+    if name not in store:
+        return jsonify({"success": False, "error": f"Preset '{name}' not found"}), 404
+    del store[name]
+    if store.get("_last") == name:
+        remaining = [k for k in store if not k.startswith("_")]
+        store["_last"] = remaining[-1] if remaining else None
+    _save_store(ptype, store)
+    return jsonify({"success": True})
+
+
 if __name__ == "__main__":
     app.run(debug=True, host="0.0.0.0", port=5000)